scholarly journals Improving the Efficiency of Measurements of Combustible Gases Concentration by a Thermocatalytic Sensor

2020 ◽  
Vol 24 (1) ◽  
pp. 189-205
Author(s):  
O. G. Bondar ◽  
E. O. Brezhneva
Keyword(s):  
Ambient Temperature ◽  
Mathematical Description ◽  
Temperature Fluctuations ◽  
Conversion Function ◽  
Temperature Stabilization ◽  
Temperature Influence ◽  
Gas Concentration ◽  
Conversion Characteristic ◽  
Combustible Gases ◽  
Tuning Out

Thermocatalytic sensors are widely used in gas analysis systems and have high reliability and low cost. However, errors in measuring the concentration of combustible gases related to the non-linearity of the conversion characteristic and the influence of ambient temperature fluctuations significantly limit the scope of their application.Purpose of reseach. Development of a method for measuring gas concentration by thermocatalytic sensors, which allows reducing measurement errors by tuning out due to ambient temperature influence and linearization of the conversion characteristic.Problems. They are as follows: to develop a method for temperature stabilization of a thermocatalytic sensor; to make a structural and functional scheme for the sensor activation; to obtain a mathematical description of the method and substantitation for tuning out as a result of temperature influence; to experimentally confirm the possibility of linearization of the sensor conversion function in the thermal stabilization mode.Methods. The mathematical description of the method applies the theory of heat transfer and the theory of electrical circuits with discrete signals. When analyzing existing solutions and synthesizing the device, methods for calculating circuits with nonlinear elements and the theory of measurement systems have been used. The real conversion function has been obtained through an experimental method.Results. A method for measuring gas concentration by a thermocatalytic sensor with the use of a microcontroller and PWM has been developed. It allows reducing errors due to tuning out as a result of ambient temperature influence. A mathematical description of the method has been given. An experiment has been performed. It demonstrates the effectiveness of using temperature stabilization to linearize the conversion characteristic.Conclusion. The paper proposes a method for temperature stabilization of thermocatalytic gas sensors. The method makes it possible to increase the accuracy of measurements by tuning out due to the influence of temperature fluctuations and linearization of the conversion function. The possibility of linearization of the sensor function has been experimentally confirmed. It characterizes the dependence of the output signal on the concentration of combustible gas. Using this method allows you to reduce the cost of the sensor, improve the quality factors of the sensor, such as the reliability and stability of parameters.

How to correct the ambient temperature influence on the thermal response test results

2015 ◽  
Vol 82 ◽  
pp. 39-47 ◽  
Author(s):  
Roque Borinaga-Treviño ◽  
Jose Norambuena-Contreras ◽  
Daniel Castro-Fresno
Keyword(s):  
Ambient Temperature ◽  
Thermal Response ◽  
Thermal Response Test ◽  
Test Results ◽  
Temperature Influence ◽  
Response Test

scholarly journals Prediction Model for Dissolved Gas Concentration in Transformer Oil Based on Modified Grey Wolf Optimizer and LSSVM with Grey Relational Analysis and Empirical Mode Decomposition

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 422 ◽  
Author(s):  
Bing Zeng ◽  
Jiang Guo ◽  
Fangqing Zhang ◽  
Wenqiang Zhu ◽  
Zhihuai Xiao ◽  
...  
Keyword(s):  
Prediction Model ◽  
Ambient Temperature ◽  
Grey Relational Analysis ◽  
Grey Wolf Optimizer ◽  
Grey Wolf ◽  
Dissolved Gas ◽  
Gas Concentration ◽  
Relational Analysis ◽  
Mode Decomposition ◽  
Grey Relational

Oil-immersed transformer is one of the most important components in the power system. The dissolved gas concentration prediction in oil is vital for early incipient fault detection of transformer. In this paper, a model for predicting the dissolved gas concentration in power transformer based on the modified grey wolf optimizer and least squares support vector machine (MGWO-LSSVM) with grey relational analysis (GRA) and empirical mode decomposition (EMD) is proposed, in which the influence of transformer load, oil temperature and ambient temperature on gas concentration is taken into consideration. Firstly, GRA is used to analyze the correlation between dissolved gas concentration and transformer load, oil temperature and ambient temperature, and the optimal feature set affecting gas concentration is extracted and selected as the input of the prediction model. Then, EMD is used to decompose the non-stationary series data of dissolved gas concentration into stationary subsequences with different scales. Finally, the MGWO-LSSVM is used to predict each subsequence, and the prediction values of all subsequences are combined to get the final result. DGA samples from two transformers are used to verify the proposed method, which shows high prediction accuracy, stronger generalization ability and robustness by comparing with LSSVM, particle swarm optimization (PSO)-LSSVM, GWO-LSSVM, MGWO-LSSVM, EMD-PSO-LSSVM, EMD-GWO-LSSVM, EMD-MGWO-LSSVM, GRA-EMD-PSO-LSSVM and GRA-EMD-GWO-LSSVM.

Influence of Environment Temperature on Strength of Quick-Setting Adhesives Based on Cyanoacrylates

2014 ◽  
Vol 1030-1032 ◽  
pp. 272-275
Author(s):  
Miroslav Müller ◽  
Petr Valášek
Keyword(s):  
Bond Strength ◽  
Production Process ◽  
Temperature Fluctuations ◽  
Adhesive Bond ◽  
Negative Influence ◽  
Temperature Influence ◽  
Adhesive Bonds ◽  
Strength Change ◽  
Environment Temperature ◽  
Adhesive Bond Strength

A primary aim of a manufacturing company is a simplicity and a speed of a production process. This assumption makes prospects in an area of sheet bonding by quik-setting adhesives (cyanoacrylates). Owing to temperature fluctuations in various climatic environments significant changes of the temperature occur. For successful application of particular products it is necessary to investigate a temperature dependence of already hardened adhesives. The paper deals with a research of the environment temperature influence on the strength change of the quick-setting adhesives. The experiment results confirmed a fundamental negative influence of the environment temperature on the strength of the adhesive bonds. A type of the failure area has not change owing to the environment temperature. The aim of the research is to set the influence of the environment temperature on the adhesive bond strength created with different cyanoacrylate adhesives.

Changes in Barometric Pressure and Ambient Temperature Influence Osteoarthritis Pain

2007 ◽  
Vol 120 (5) ◽  
pp. 429-434 ◽  
Author(s):  
Tim McAlindon ◽  
Margaret Formica ◽  
Christopher H. Schmid ◽  
Jeremiah Fletcher
Keyword(s):  
Ambient Temperature ◽  
Barometric Pressure ◽  
Temperature Influence ◽  
Osteoarthritis Pain

scholarly journals THERMODYNAMICS IN NESTS OF TWO MELIPONA SPECIES IN BRASIL

1983 ◽  
Vol 13 (2) ◽  
pp. 453-466 ◽  
Author(s):  
David W. Roubik ◽  
◽  
Francisco Javier Aquilera Peralta ◽  
Keyword(s):  
Ambient Temperature ◽  
Time Lag ◽  
Temperature Fluctuations ◽  
Nest Structure ◽  
Brood Chamber ◽  
Nest Cavity ◽  
Melipona Species ◽  
Brood Temperature ◽  
Average Brood ◽  
Brood Nest

SUMMARY Thermodynamics within 10 nests of Melipona rufiventris and M. seminigra were recorded during 48 horurs with thermocouple probes. Strikingly similar patterns were found for both species. Homeostasis did not occur; temperatures within the brood area, honey and pollen stored in pots and nest cavity space all followed ambient temperature fluctuations. Nest temperatures were consistently higher than ambient in all portions of the nest except the upper extremith of vertically elongate hives. Near the brood, temperature fluctuations were damped and displayed a time lag of one to two hours in following ambient temperature. The thoracic temperature of resting worker bees was near 34°C, and the average brood temperature was 31 — 32°. The involucrum surrounding the brood retained a portion of radiated heat from immatures and workers resting between combs, and brood temperature was two to three degrees higher than internal nest temperature immediately outside the involucrum. The brood chamber, the largest nest structure, contained from 2000 to 6000 immatures, and adult bee populations were less than 1000. The brood nest acts as a heat source at the base of the nest and dissipates heat upwards, creating a thermal gradient. Immature bees appear to supply most of the heat for the nest, and excess heat is shunted by fanning workers through the nest entrance, usually connected to the brood area. There is no evidence of evaporative cooling from water brought into the nest in these or other species of Meliponinae.

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